Relevant prior art hydrofoil devices include the “Trampofoil” device disclosed in Swedish Design Patent no. 98-0088 and a Water Vehicle disclosed in U.S. Pat. No. 6,099,369 issued to Puzey.
The Trampofoil discloses a basic self-propelled hydrofoil device having a main foil in the rear and a steerable foil in the front. The '369 patent issued to Puzey discloses a related device that has a biased pivot point located substantially above the rear foil, i.e., under the area at which a user stands when in use (FIG. 9, item 82, or FIG. 10, item 72).
Disadvantageous aspects of the Trampofoil device and the '369 patent include that they may not permit the front edge of the rear or “drive” foil to tilt sufficiently downward in response to a driving leg thrust to adequately propel the craft forward. A significant amount of the downward leg force may thus be impaled upon the foil, rather than shearing through water—wasting significant driving energy. In addition, the steering shaft of the Trampofoil is made of fiberglass which bends not only in the direction of travel, but also laterally, making steering difficult.
Due to these and other disadvantageous aspects, the arrangement of the Trampofoil and that of the '369 patent are difficult to use, particularly by lay persons.
A need thus exists for a hydrofoil device that may be configured for self-propelled operation and is relatively easy to use. A need also exists for a hydrofoil device that provides sufficient forward thrust for the energy expended by the downward thrust of an operators leg's (or other means).